BEHAVIOR OF ENDODERMAL BUTTON CELLS DURING METAMORPHOSIS OF ASCIDIAN LARVAE

Swimming larvae of Phallusia mamillata are known to have <<button cell s>> of endodermal origin between the ventral surface of the pharynx an d the epidermis, that are stainable by various techniques. By immunofl uorescence with anti-tubulin antibody and confocal laser microscopy, w e obtained a bright reaction at one pole of the cells, suggesting the presence of a cap of tubulin and of microtubules overlaying the nucleu s. During metamorphosis the microtubule-rich pseudopods at their base reach the epidermis, especially in the area near the adhesive papillae . Then they emigrate through the epidermis and become roundish again.